The reaction of dibasic acids, or the corresponding esters or acid halides, with diamines or diols to produce open chain polyamides or polyesters is well known in the art. Such polymers are typically thermoplastics with an established utility in a number of applications. A commercial example of such an open chain polyamide is the polymer produced by reaction of hexanedioic acid (adipic acid) and hexamethylenediamine known as Nylon 66 and marketed by DuPont.
A second class of polymeric materials is based in part on difunctional monomers having cyclic or in some cases polycyclic structures within the molecule. These monomers are often thermosetting resins which are typically useful in high temperature applications in part because of the cyclic structure which often leads to properties of strength and rigidity at elevated temperature. It would be of advantage to provide a process for the conversion of open chain dicarboxylic acid compounds to novel products of cyclic or polycyclic structure having useful properties and thereby increase the breadth of utility for the dicarboxylic acid compounds.
A class of compounds having a polycyclic structure is the class of spirodilactones represented by 1,6-dioxaspiro[4.4]nonane-2,7-dione. This spirodilactone is known, being prepared, for example, by Pariza et al, Synthetic Communications, Vol. (13) 3, pp. 243-254 (1983). This spirodilactone has demonstrated utility as a curing agent in epoxy resin systems which do not shrink upon curing. This dimensional stability is thought to result from opening of the lactone ring(s) during the curing process. See knowles et al, J. Appl. Polymer Sci., Vol 10 (6), pp. 887-888 (1966). It is generally considered characteristic of the spirodilactone ring system that reaction with active hydrogen compounds tends to produce ring-opened derivatives, as exemplified by the above Pariza et al publication and by Cowsar, U.S. Pat. No. 4,064,086. It would be of advantage to provide a process for converting the spirodilactone ring system into novel functional derivatives while maintaining the spiro ring system.